The present invention relates to display units, and particularly to display units that exhibit two or more consecutively changing images to be viewed by a viewer.
Multiple image display devices of various kinds are known; among them are those comprising lenticular lenses in array with multi-dimensional lithographs moving in parallel planes. Such displays are described in U.S. Pat. No. 5,100,300 (Sediguchi) and U.S. Pat. No. 5,488,451 (Goggins), and also in U.S. patent application Ser. No. 09/248,318. The devices described in these documents relate basically to small-sized units, mainly for indoor use. These devices, however, prove to be inadequate for large-sized displays such as outdoor billboards.
The basic optical principles of these devices require an accurate positioning of the linear lenses in juxtaposition with the lithographic film. When large-sized displays are involved, such accuracy cannot be adequately achieved. Thermal changes and inconsistencies of printing processes are the main causes of such a drawback. U.S. Pat. 5,146,703 (Boden) and others tried to overcome this difficulty, but the fact that billboards based on the aforementioned optic principle are not in commercial use, suggests that an adequate device has not yet been devised.
Japanese Patent 0211437 (Kumagai) discloses a large-sized display having a cylindrical lens group, a framed body which supports an image carrier constituted of a transparent printing positive, and a light source at its rear face. The image processing of such a system imposes accurate positioning of the image carrier in close juxtaposition with the lenticular panel. Such conditions are achieved by the Kumagai device, which utilizes a rigid frame sliding along mechanical guide means disposed at a constant spacing from the lens group. Thus, an expensive and complicated solution is proposed, which also has its limitations regarding size and accuracy relationships between the lithographic prints and the lenses.
It is the object of the present invention to provide a display unit which ameliorates the above-described disadvantages of the prior art devices. It is a further object of the present invention to provide a low-cost display unit having disposable lithographic film of a large size disposed in close juxtaposition to the lenticular panel at an accurate distance from the lenses, for achieving a clear display of the images printed on the film, including changing images and stereoscopic animation.
It is a still further object of the present invention to provide a custom-made display unit consisting of only two fundamental parts: a lenticular panel and a lithographic film, without requiring a rear panel or frame, the unit being configured to be integrated into a custom-made platform of any shape or a light-box of any size, and which can also advantageously serve as a stand-alone product at points of sale, without connection to the electrical mains.
A yet further object of the invention is to provide a large-sized display unit for outdoor use that is capable of functioning in changing conditions of temperature and despite inaccuracies of the printing process.
In accordance with the present invention, there is therefore provided a display unit for displaying two or more consecutively changing images, said unit comprising a curved lenticular panel having front and rear faces; a displaceable, lightweight, image-carrying film spread out along said rear face; an electric drive coupled to said film for periodically displacing the film across the lenses of said panel, and guide means facilitating the smooth reciprocating movement of said film.